A soldier of the Kenyan Contingent serving with the African Union Mission in Somalia (AMISOM) stands guard on a street in the centre of the southern Somali port city of Kismayo while a combat engineering team inspects the surrounding area following reports of a suspected improvised explosive device (IED) left behind by the Al-Qaeda-affiliated extremist group Al Shabaab. (STUART PRICE/AFP/Getty Images)

The extremist Somali group al-Shabab is offering fighters an $8,000 reward if they kill Kenyan security forces, according to intelligence data cited by Al Jazeera.

Garissa county commissioner Maalim Mohammed said officials had intercepted a radio message in which the radical group offered bounty figures dictated by the Kenyan victim officer's rank, according to Al Jazeera.

Mohammed thought the money would probably motivate impoverished youths in the eastern Kenyan town, putting security officers stationed there -- even those serving in plainclothes -- at great risk, reported the Associated Press.

But Muslim Human Rights Forum head Al-Amin Kimathi told AP people would be more likely to help al-Shabab, a group believed tied to Al Qaeda, for religious over financial reasons.

“They think they are doing this because of jihad and will go to any extent to defend their positions, however misguided," he said.

The town of Garissa is mostly inhabited by ethnic Somalis of Kenyan citizenship, according to AP.

Kenyan military spokesman Colonel Cyrus Oguna confirmed to Al Jazeera that al-Shabab is offering $8,000 for the death of leading officer Lieutenant Colonel Jeff Nyaga.

Nyaga has been instrumental in Kenyan military efforts in southern Somalia, where the government is leading an offensive against a militant stronghold.

Al Jazeera's Nairobi correspondent Peter Greste said the bounty offers have not yet been officially confirmed but Kenyan officials are very concerned over the reports.